/*
   ============================================================================
	csrec.c -- Motorola S record format checker
	Version 3 -- 1987-07-10 -- D.N. Lynx Crowe
   ============================================================================
*/

#define	CHECKER		0	/* define non-zero for main */

#if	CHECKER

#define	MAXBUFLN	2048	/* big enough for the longest expected record */

#include "stdio.h"

char	iobuf[MAXBUFLN+1];
char	*fileid;

#endif

#include <stddefs.h>
#include <ctype.h>

#define	SREC9	"04000000FB"

static	char	ahex[] = "0123456789abcdefABCDEF";

/*  */

/*
   ============================================================================
	memcmpu -- compare two memory areas while ignoring case
   ============================================================================
*/

int
memcmpu(s1, s2, n)
register char *s1, *s2;
int n;
{
	register int c1, c2;

	while (n) {

		c1 = 0377 & *s1++;
		c2 = 0377 & *s2++;

		if (isascii(c1) && islower(c1))
			c1 = _toupper(c1);

		if (isascii(c2) && islower(c2))
			c2 = _toupper(c2);

		if (c1 < c2)
			return(-1);

		if (c1 > c2)
			return(1);

		n--;
	}

	return(0);
}
		
/*  */

/*
   ============================================================================
	xdtoi -- convert hex ASCII to an int digit
   ============================================================================
*/

static int
xdtoi(c)
register int c;
{
	register int i;
	register char *ap = &ahex[0];

	for (i = 0; i < 22; i++)
		if (c EQ *ap++)
			if (i >15)
				return(i - 6);
			else
				return(i);

	return(-1);
}

/*  */

/*
   ============================================================================
	csrec -- check a Motorola S record for errors
   ============================================================================
*/

int
csrec(line)
register char *line;
{
	register int	c, len, i;

	int	csum, val;

	if ('S' NE (c = *line++))
		return(-1);

	switch (c = *line++) {

	case '2':

		csum = 0;

		if (isxdigit(c = *line++))
			len = xdtoi(c);
		else
			return(-1);

		if (isxdigit(c = *line++))
			len = (len << 4) + xdtoi(c);
		else
			return(-1);

		csum += (len & 0377);
		len -= 4;

		for (i = 0; i < 3; i++) {

			if (isxdigit(c = *line++))
				val = xdtoi(c);
			else
				return(-1);

			if (isxdigit(c = *line++))
				val = (val << 4) + xdtoi(c);
			else
				return(-1);

			csum += (val & 0377);
		}

		for (i = 0; i < len; i++) {

			if (isxdigit(c = *line++))
				val = xdtoi(c);
			else
				return(-1);

			if (isxdigit(c = *line++))
				val = (val << 4) + xdtoi(c);
			else
				return(-1);

			csum += (val & 0377);
		}

		csum = 0377 & ~csum;

		if (isxdigit(c = *line++))
			val = xdtoi(c);
		else
			return(-1);

		if (isxdigit(c = *line++))
			val = (val << 4) + xdtoi(c);
		else
			return(-1);

		if (csum NE (val & 0377))
			return(-1);

		return(1);

	case '9':

		if (memcmpu(line, SREC9, 10) EQ 0)
			return(0);
		else
			return(-1);

	default:

		return(-1);
	}

	return(-1);
}

/*  */

#if	CHECKER

main(argc, argv)
int argc;
char **argv;
{
	FILE	*sfile;
	int	rc;
	long	recnum;

	if (argc < 2) {

		printf("csrec:  No file specified on input line.\n");
		printf("csrec:  Using stdin for input.\n");
		sfile = stdin;
		fileid = "stdin";

	} else {

		++argv;
		fileid = *argv;

		if (NULL EQ (sfile = fopena(fileid, "r")) ) {

			printf("csrec:  Unable to open [%s]\n", fileid);
			printf("csrec:  Processing aborted.\n");
			exit(1);
		}
	}

	recnum = 0L;

	do {

		recnum++;
		memset(iobuf, ' ', MAXBUFLN+1);
		rc = fgets(iobuf, MAXBUFLN, sfile);

		if (rc EQ NULL) {

			printf("csrec:  Could not read record %ld on [%s]\n",
				recnum, fileid);

			if (sfile NE stdin)
				fclose(sfile);

			printf("csrec:  Processing aborted.\n");
			exit(1);
		}

		if ((rc =csrec(iobuf)) < 0) {

			printf("csrec:  Record %ld on [%s] is in error\n",
				recnum, fileid);

			if (sfile NE stdin)
				fclose(sfile);

			printf("csrec:  Processing aborted.\n");
			exit(1);
		}

	} while (rc);

	if (sfile NE stdin)
		fclose(sfile);

	printf("csrec:  S-Record file [%s] is valid\n", fileid);
	printf("csrec:  Processing complete.\n");
	exit(0);
}

#endif